JPH037809B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates generally to friction clutches and, more particularly, to resiliently loaded lever actuation mechanisms for such clutches.

Lever actuation mechanisms for friction clutches require some axial space to enable the lever to perform its desired declutching function. To reduce the axial length of the clutch, it is common to provide an annular belleville or disc spring to provide the necessary elastic loading. One method involves internally positioning a disc spring between the clutch cover and the pressure plate, and arranging each lever such that each lever exerts a tensile action on the pressure plate to overcome the disc spring load on the pressure plate. . Another method is to position a disc spring externally between the clutch cover and each lever so that the levers carry the entire spring load.

This latter arrangement is preferable to the former method because it positions the disc spring entirely outside the cover. In this case, the lack of contact between the disc spring and the pressure plate prevents direct heat conduction from the pressure plate to the disc spring. Another advantage of this construction is that the disc spring on the lever
The reason is that they are in constant contact whether they are in the released position or in the engaged position. In this case, no interference fit or additional parts of the lever are required to hold the lever against rattling. In a structure using a disc spring as described above, it is necessary to properly position the disc spring relative to the clutch actuating components so that the disc spring performs its intended function.

Although structures exist that provide satisfactory operation and control of such disc springs, these structures are complex and require more space than is conventionally available in a vehicle.

The present invention includes a plurality of radially extending clutch release levers and an annular spring located between the levers and a cover of the friction clutch, the annular spring being located externally of the cover. The present invention relates to a drive mechanism for a friction clutch.

Embodiments of the friction clutch of the present invention will now be described in detail with reference to the accompanying drawings.

A friction clutch 10 according to a preferred embodiment of the invention shown in FIGS. 1 and 2 has a central axis -
have. The friction clutch 10 comprises an annular cover 12 with a peripheral flange portion 13 fastened to the rear face of a drive member 14, for example a standard flywheel, by a plurality of circumferentially spaced bolts 16, the cover 12 being connected to the drive member It is designed to rotate together with 14. Cover 12 further includes a generally axially extending rim portion 18 and rim portion 1 .
8 and an end wall 20 extending radially inwardly from 8 . This end wall 20 terminates in an inclined section 22 arranged at an angle. A central hole 24 in the end wall 20 is formed in the radially inner portion of the ramp 22 .

An annular space 26 is provided between the drive member 14 and the cover 12 to receive a pressure plate 28. A driven member 30, for example a driven disk, is connected to the pressure plate 2.
8 and the drive member 14.

The driven member 30 includes a central boss 32 to which a support plate 34 is fixed, and friction facings 36 are fastened to opposite sides of the outer periphery of the support plate 34. The central boss 32 is splined to the outer end of the transmission input shaft 38 and has a friction facing 36.
is located between the pressure plate 28 and the drive member 14. This spline connection allows the driven member 30 to
can be freely moved axially relative to the input shaft 38 and rotated together with the input shaft 38.

The pressure plate 28 is axially movable and engages the driven member 30 so as to move the driven member 30 into the drive member 14.
The rotatable driving member 14 and the driven member 30 of the friction clutch of the present invention are connected to each other so as to transmit driving force. A plurality of circumferentially spaced drive bands 40 rotatably connect pressure plate 28 to cover 12 and provide limited axial movement of pressure plate 28 relative to cover 12. Drive band 40 further acts as a member to lift pressure plate 28 away from drive member 14 when moving friction clutch 10 to its disengaged position.
Opposing ends of each drive band 40 are connected to cover 12 and pressure plate 28 in a conventional manner.

A lever actuation mechanism is provided to move the pressure plate 28 axially relative to the cover 12 into and out of engagement with the driven member 30. The lever actuating mechanism includes a plurality of radially extending covers 42 located entirely outside the cover 12 and pivotally connected to the cover 12 by pivot pins 44. Outer end 46 of this cover
engages a head 48 formed on a screw piece 50 that is tightened to the pressure plate 28.

A resilient member is provided to apply an axial engagement force to the pressure plate 28, and the pressure plate 28 is normally biased to engage the driven member 30 to apply a clamping force. The resilient member maintains a substantially constant engagement pressure regardless of wear of the friction facings 36 of the driven member 30. In the preferred embodiment, the resilient member is an annular spring 54 in the form of a Belleville spring compressed between the cover 12 and each lever 42. When the annular spring 54 is not subjected to stress, it has a conical shape with an inner peripheral portion 60 and an intermediate conical portion 6.
2 and an outer peripheral portion 64. The inner peripheral portion 60 and the outer peripheral portion 64 are axially spaced apart from each other in the unstressed state, but the annular spring 5
4 are brought into a compressed state, as shown in FIG. 2, they approach each other so that they are located in the same plane. The annular spring 54 connects the inner peripheral portion 60 (fixed) to the cover 1
2, and the outer peripheral portion 64 (movable) is engaged with the lever 42 and is movable together with the lever 42. Due to the movement of the annular spring 54, the cover 1
The inclined portion 22 of No. 2 is sufficiently inclined to allow clearance during operation.

In disengaging the clutch, each lever 42 is moved against the action of the annular spring 54 by a throw-out bearing 66 acting on the inner end 68 of the lever 42. It is arranged so as to press the annular spring 54. To engage the clutch, release the coupling and release bearing 66 from the inner end 68 and release the lever 42.
is pivoted about pin 44 by the biasing force of annular spring 54 so that outer end 46 moves pressure plate 28 toward driven member 30, thereby clamping driven member 30 against drive member 14. .

An annular collection ring 70 is provided to evenly distribute the loads and stresses from the annular spring 54 to the lever 42. The collection ring 70 is cup-shaped in cross-section and includes an axially extending rim 72 surrounding an outer peripheral portion 64 of the annular spring 54 and an annular base 7 extending radially inwardly.
4. The base 74 is positioned between the rear surface of the annular spring 54 and the adjacent front surface of the lever 42. That is, the base 74 transmits the reaction load of the annular spring 54 to each lever 42 . The base 74 is oriented at a slight angle to provide clearance to the outer peripheral portion 64 of the annular spring when each lever 42 is pivoted to its disengaged position.

The collection ring 70 has sufficient clearance relative to the outer peripheral portion 64 of the annular spring 54 to allow it to move freely during the various stages of clutch actuation. Each lever 4
2 is in constant contact with the base 74 of the collection ring 70, so that each lever 42 pushes the collection ring 70 against the annular spring 54.
It acts by pressing against and holding it in place. If desired, the annular spring 54 may act directly on each lever 42. However, by providing an annular collecting ring 70 to avoid concentrating the engagement load immediately below each lever 42, an even distribution of the load is achieved.

A spring restraining member is attached to the cover 12. This spring restraining member is connected to the inclined portion 2 of the cover 12.
The friction clutch 10 includes a plurality of circumferentially spaced tabs 76 extending inwardly from the friction clutch 2 toward the central axis of the friction clutch 10. Each ear piece 76
A lip portion 78 is integrally formed at the inner end portion of the clutch member and extends outwardly in a direction parallel to the clutch axis. The lip 78 further includes a recess 80 for receiving a positioning member formed as an integral part of the annular spring 54, as shown in FIG. a stop member 82 comprising angularly spaced shoulders formed therein by a recess 80;
is obtained.

The positioning member of the annular spring 54 consists of a plurality of circumferentially spaced tongues 84 extending inwardly from the inner peripheral portion 60 of the annular spring. Each tongue 84 is equal in number to the recesses 80 and sized to closely fit the contour of the recesses 80. Therefore, the positioning member of the annular spring 54 and the restraining member of the cover 12 cooperate to move the annular spring 54 toward the center axis of the friction clutch 10.
to prevent relative rotation between the annular spring 54 and the cover 12. Tongue piece 8
4 and the recess 80 is dimensioned to provide the necessary clearance for the deformation of the annular spring 54 as it flattens during its operation. The spaced inner edges of the inner end of the tongue 84 form a stop member 86 that can engage the inner surface of the stop member 82, which is the diagonal shoulder of the recess 80. The dimensional tolerances are such that the top surface of the recess 80 and the mating bottom surface of the tongue 84 cooperate with each other to position the annular spring 54 concentrically about the central axis of the friction clutch 10. Further, the inner edge of the tongue 84, the stop member 86, cooperates with the mating inner surface of the oblique shoulder of the recess 80, the stop member 82, to prevent rotation of the annular spring 54 relative to the cover 12. .

In the structure described above, by providing the tongue-shaped piece 84 on the inner peripheral portion 60 of the annular spring 54,
Tongue 84 from outer peripheral portion 64 of annular spring 54
The distance to the inner edge of is substantially increased. In this case, at the positions of the circumferentially spaced tongues, the intermediate conical portion 62 of the annular spring 54 becomes radially longer and the deflection of the annular spring 54 increases without an increase in load.

The diagram of FIG. 7 shows a comparison between the annular spring 54 used in the friction clutch of the present invention and a standard Belleville spring. The deflection curve shown by dashed line A results from a standard disc spring. For comparison, solid line B is the first
6 shows the deflection curve resulting from the annular spring 54 with the tongue 84 illustrated in FIGS. The peak load is designated P and the negative percentage portion of the curve is designated N.

In the preferred embodiment, the inner bottom edge of the tongue 84 of the annular spring 54 engages and acts against the outer surface of the ear 76, while the outer peripheral portion 64 of the annular spring 54
A reaction force is exerted on the inside of each lever 42 via the collecting ring 70 . That is, the tongue 84 forms a plurality of circumferentially spaced reaction surfaces on the inner periphery of the annular spring 54, whereas the active surface on the outer periphery of the annular spring 54 is annular.

As shown in cross section in FIG. 4, the ramp 22, the lug 76 and the lip 78 of the cover 12 form a generally L-shaped leg, and the entire tongue 84 of the annular spring 54 is shaped like a lip. It is within the area of section 78. In the variant illustrated in FIG. 6, the tongue 84 of the annular spring 54
At least one of the engageable lips 78 is provided with an integral contact to indicate when the friction clutch 10 is in a fully worn position. Each lip 78 preferably has an integral contact portion to maintain balance and proper indication of wear. This contact portion 88 consists of an outwardly extending flange;
The contact portion 88 is integral with the lip portion 78 and extends in a direction substantially perpendicular to the central axis of the friction clutch 10. The radially outermost inner edge of lip 78 forms a fixed stop 90 .
The stop piece 90 engages the outer surface of the tongue 84 of the annular spring 54 and causes the annular spring 54 to bottom out or protrude position when the friction clutch 10 is in the fully worn position. (overcenter
It is designed to work so that it does not become a position).

The contact portion 88 is bent upwardly at a selected angle so that the fixed stopper piece 90
is located at a point corresponding to the fully worn position of the clutch. Although the contact portions 88 are shown extending in a direction perpendicular to the clutch axis, the contact portions 88 may be disposed diagonally on each side to position the stopper 90 in a desired position. Existence of contact portion 88 and stopper piece 90
The position of the annular spring 54 causes the driven member 30 to
can be stopped at a position consistent with the wear of the stationary friction facings. In this respect, each lever 42 senses the effects of free movement or no load. In this case, the operator is informed that the friction clutch is worn out.

In the normally engaged position of friction clutch 10, as shown in FIG. It is placed in relation to the part. As shown, the annular spring 54 is assembled under initial compression;
The inner peripheral portion 60 and outer peripheral portion 64 are arranged close to each other in the axial direction. The outer circumferential portion 64 is pushed towards the ramp 22 via the lever 42 by the uncoupling bearing 66 . During the clutch release operation, the inner and outer peripheral portions flex further toward a common plane (flattening out), as shown by the dashed line R in FIG. The lever 42 then pivots about the pivot pin 44 and pivots the outer end 46 away from the head 48 of the screw 50 attached to the pressure plate 28, thereby forcing the pressure plate 28 against the driven member 30. The pressure is removed and the driven member 30 and drive member 14 are disengaged. As the friction facing 30 wears, the inner and outer peripheral portions move further apart from each other in the axial direction, approaching the free or unstressed relaxed state of the annular spring 54. The position of the contact portion 88 and its stopper piece 90 is such that the outer surface of the tongue-like piece 84 contacts the stopper piece 90 and the annular spring 5
4 does not reach a position beyond the position indicated by the chain line W in FIG. The dashed line W indicates the position of the annular spring 54 when the clutch is sufficiently worn. In this position, the annular spring 54 is
From the initial compressed state, it returns to its original unstressed, undeformed state and no longer responds to apply a biasing force on the inside of each lever 42.

It is clear that instead of the conical shape shown, other fixed annular springs may be used, such as slotted, fingered, curved shapes, as well as single or laminated wave washer shaped springs.

As is clear from the above description, the advantages of the present invention are that the spring restraining member (a plurality of ears 76) formed on the cover 12 of the friction clutch 10 and the annular spring 5
4 (a plurality of tongue-like pieces 8)
4). The construction is such that satisfactory operative connection of the components within a limited axial space is achieved.
Additionally, the provision of a collector ring 70 for evenly distributing the load on each lever 42 and a modified wear-indicating structure provide additional advantages to this type of clutch.

Although the present invention has been described above in detail with reference to its embodiments, it goes without saying that the present embodiments can be modified in various ways without departing from the spirit of the invention.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing one embodiment of the friction clutch of the present invention, and FIG. 2 is a 2-2 part in FIG.
3 is a partially enlarged rear view of the cover and annular spring of the friction clutch shown in FIG. 2, FIG. 4 is a sectional view taken along line 4-4 in FIG. 3, and FIG.
FIG. 6 is a cross-sectional view similar to FIG. 4 of a modification of FIG. 4; FIG. 7 is a load versus deflection diagram of the annular spring of the friction clutch of the present invention. . 10...Friction clutch, 12...Cover, 14
... Drive member (flywheel), 28 ... Pressure plate, 3
0...Followed member (driven disc), 42...Lever,
54... Annular spring, 60... Inner peripheral portion, 64...
...outer peripheral part, 76...ear piece, 78...lip-shaped part,
84... tongue-like piece, 82, 86... stop member, 9
0...Stopping piece.

Claims (1)

[Scope of Claims] 1. (a) A driving member and a driven member that are rotatable around a central axis, and (b) a cover that is fixed to the driving member and does not move in the axial direction so as to rotate together with the driving member. (c) an axially movable pressure plate coupled to said cover for rotation with said cover and limited axial movement relative to said cover; and (d) an axially movable pressure plate connected to said cover. (e) a pivotable lever disposed on the outside of the cover for axially moving the pressure plate into and out of engagement with the driven member; an annular disc spring compressed between the drive member and the driven member, the spring having an inner circumferential portion and an outer circumferential portion, and engaging the lever and movable together with the lever; In a friction clutch which is connected to transmit the following: (i) a plurality of ears spaced apart from each other in the circumferential direction, and a lip-like part formed integrally with these ears and forming a recess; (ii) circumferentially spaced disc spring restraining members attached to the cover; (iii) a positioning member attached to the disc spring comprising a plurality of tongues; and (iii) a positioning member provided in the tongue and the recess for relative rotational movement between the cover and the disc spring. A friction clutch characterized in that it is provided with a stop member that is mutually engageable to prevent the friction. 2. A friction clutch according to claim 1, wherein said cover is provided with a contact portion capable of engaging said disc spring when said friction clutch is in a fully worn clutch position. 3. The friction clutch according to claim 2, wherein the lug, the lip, and the contact portion form a U-shaped groove for receiving the tongue of the disc spring. 4 the ear piece extends inward toward the central axis;
2. A friction clutch according to claim 1, wherein said lip extends outwardly parallel to said central axis and said tongue of said disc spring extends inwardly toward said central axis. 5, the positioning member extending inwardly from the inner periphery of the disc spring, and providing an annular collection ring surrounding the outer periphery of the disc spring, the collection ring engaging the lever; 2. A friction clutch according to claim 1, which is adapted to move together.